Tree Blocks Wooden w/Bark 22 Piece Math Real Wood Building Block Set - 954502 Tree Blocks free them up to think of building in other terms, not just squares...encouraging creativity. The blocks are made from recycled fruit tree wood. Blocks are precision cut into specific lengths of 2 cm, 4 cm, 6 cm, 8 cm and 10 cm. Ages 3 yrs and up as they may contain small parts that are a choking hazard. Made in the USA.